Motion controls were considered fro Smash Bros. Brawl

Coming from a classic interview with Masahiro Sakurai before Brawl came out, as translated by Source Gaming...

Q: How will Super Smash Bros. for Wii take advantage of the controller?

Mr. Sakurai: We’ve actually been working with some different ideas, and we’ve found that trying to implement too much of the motion sensor could actually get in the way of the game. We’re looking at trying to keep the controls simple, as they have been in past games. Of course, you all know that the Wii hardware has ports for the GameCube controller as well. So, I’ll just say now that you may not want to throw away your GameCube controllers just yet!

Mr. Miyamoto and Nintendo have encouraged developers to really take advantage of the Wii Controller and find innovative ways to implement it into their games. So in that sense, I’m going in a different direction, and trying to offer something that has more of the standard control features that all of you have come to expect.

from GoNintendo